Differential Expression and Regulation of Angiopoietin‐3 in Mouse Uterus during Preimplantation Period

Abstract

Angiogenesis is necessary for successful implantation and decidualization. This study was to investigate the differential expression of angiopoietin-3 (Ang-3) in mouse uterus during early pregnancy and its regulation by steroid hormones using in situ hybridization and reverse transcription polymerase chain reaction (RT-PCR). There was no detectable Ang-3 mRNA signal on days 1-5 of pregnancy by in situ hybridization. On day 6 of pregnancy, a low level of Ang-3 mRNA signal was seen in the primary decidua. Ang-3 mRNA expression gradually increased on days 7 and 8 of pregnancy along with the development of decidua, and its expression scope was also expanded. The RT-PCR result indicated that Ang-3 mRNA expression was low on days 1-4 of pregnancy. On day 5, as embryo implanted, Ang-3 mRNA was highly expressed in mouse uterus, and the expression gradually increased on days 6-8 of pregnancy, with peak level on day 8 of pregnancy. Similarly, Ang-3 mRNA was also strongly expressed in decidualized cells under artificial decidualization. Compared with the delayed uterus, a high level of Ang-3 mRNA expression was detected in activated implantation uterus by RT-PCR. In the ovariectomized mouse uterus, Ang-3 mRNA expression increased and reached the highest level at 12 hr after injection of estrogen, progesterone, and estrogen plus progesterone, respectively. These results suggest that Ang-3 may play an important role during the process of mouse decidualization. Both estrogen and progesterone can induce the expression of Ang-3 in ovariectomized mouse uterus.